(1) Field of the Invention
This invention relates to a passive seat belt system suitable for use in a vehicle such as passenger car or the like.
(2) Description of the Prior Art
Pertaining to the so-called passive seat belt systems in each of which the webbing is automatically guided between the occupant-restraining position and occupant-releasing position in accordance with the getting-on and getting-off of an occupant, there have been proposed in recent years a variety of systems which have been improved in operation, reliability, etc. Many of such systems are each equipped with a guide rail provided on a vehicle body and a runner movable along the guide rail so as to guide one end or an intermediate portion of the webbing, whereby guiding the webbing to the occupant-restraining position or occupant-releasing position owing to a movement of the runner.
Other proposals have also been made on locking devices which are each adapted to lock its respective runner on a fixing member secured on a vehicle body so that the restraint of the occupant is ensured in the case of an emergency such as vehicle collision, overturn or the like.
Since most of conventionally-proposed locking devices are however of such type that a runner is locked directly, such locking devices are imposed by a serious limitation that their installation positions must be adjacent to the positions of their corresponding runners which have brought their respective webbings to the occupant-restraining positions thereof. When using especially an emergency locking device as a locking device, it is necessary to have at least one inertia-sensing member adapted to detect a variation in speed of a vehicle and a locking member operable by the inertia-sensing member. It is thus desired to permit free selection of its installation position, because such a locking device is accompanied by a difficulty in view of its installation space and a possible danger of producing vibratory noises near the occupant's head and of giving unpleasant feeling to him if such members have to be provided in an upper part of the center pillar or adjacent to the roof side.